Exploration for oil and gas in subsurface environments has historically been done using seismic imaging techniques that are now well known in the art. Exploration for minerals has historically been done using a wider variety of techniques including gravimetric, magnetics, electromagnetics, and induced polarization techniques that are well known in the art. All these imaging techniques attempt to identify a subsurface anomalous physical property (acoustic velocity, density, susceptibility, etc.) space that may be indicative of a mineral deposit. The utility of magnetic field data has also become prevalent in many areas of geophysical exploration, and including the application of 3D voxel inversion to aid in this magnetic data interpretation. Generally, voxel based inversions use magnetic field data from a magnetic response arising from induction—that is from the magnetic field emitted by a particular anomalous magnetization zone. It has recently been discovered that external influences on the induced magnetic field of the magnetization space, particularly during inversion, may be having a disproportionate impact on the model being generated. These external factors, also referred to as remnant magnetization typically affects crustal rocks as well as zones of mineralization. Note that we use the term “remnant magnetization” herein to include all non-induced magnetization effects, including but not limited to, magnetic remanence, demagnetization, and magnetic anisotropy. Unfortunately, remnant magnetization can seriously distort inversion based on the assumption that the source is only induced magnetization. The severity of the distortion is due to the highly non-unique nature of potential field inversion making it extraordinarily easy for a potential field inversion to produce a seemingly plausible model which agrees satisfactorily with the observed data, even when a fundamental assumption in the inversion is flawed.
There is a need in the art to solve one or more of the above-identified problems with the prior art and for an improved method and system for earth modelling, and particularly for earth modelling of regions having one or more anomalous magnetization zones.